Re: mtd_oobtest fails with GPMI-NAND

[Stefan Roese <sr@denx.de>]

Hi Vikram,

I might be seeing something similar on my iMX6 board. Here
mtd_subpagetest sometimes fails.

What is the current status on your platform? Did you resolve this
problem? If yes, what did you have to change/fix?

Thanks,
Stefan

On 02/02/2013 07:41 AM, Vikram Narayanan wrote:
> On 1/30/2013 7:57 AM, Huang Shijie wrote:
>> 于 2013年01月30日 00:28, Vikram Narayanan 写道:
>>> On 1/29/2013 8:06 AM, Huang Shijie wrote:
>>>>> May I know in what way the driver is restricted for using with other
>>>>> boards?
>>>> The devicetree. Please check the dts file in arch/arm/boot/dts/.
>>>> If there is no dts file for your board, the gpmi will not works very
>>>> well for your board.
>>>> for example, there is arch/arm/boot/dts/imx6q-arm2.dts for the MX6Q-ARM2
>>>> board.
>>>
>>> I've a valid dts file for my board which is good enough to probe the
>>> Toshiba NAND on-board and mount a UBIFS filesystem.
>> could you tell the dts file for your board?
>> are you sure the pinmux settings are right?
> 
> I'm using the same pinumx settings mentioned in the file
> "arch/arm/boot/dts/imx6q.dtsi". Hope that is right.
> 
>>>
>>>>> You're right and we knew it earlier as the Kernel detects the OOB size
>>>>> as 128 bytes. So, some remaining bytes become unused at the end of
>>>>> each page. i.e., (224-128). Instead of supporting ecc strength as ECC9
>>>>> we end up using ECC8. Should this be a cause for the -74 error?
>>>> no. this is not the cause. even you get the wrong geometry of the nand
>>>> chip. the gpmi still can works.
>>>>
>>>> I think the root cause is the devicetree issue as above.
>>>
>>> Something else is causing the issue. Can you give some other pointers
>>> which can potentially cause this -74 error while mounting?
>> the -74 error is the EBADMSG, it's caused by the uncorrectable ECC failure.
>> There are many reasons can cause this error:
>>     [1] the pinmux setting is not right, the gpmi does not works well.
> 
> As said above, my pinmux settings are right. GPMI detects my NAND, does 
> read/write/erase/mount. At times I'm seeing this -74 issue. Sometimes 
> this error goes off in the next reboot.
> 
>>     [2] the wrong setting of BCH. for example, the page size is 8K, you
>> set 4k to BCH.
>>         so you can set the correct nand geometry parameters for your
>> nand chip firstly, and then do the debug.
> 
>  From the driver I understood that the geometry are determined according 
> to the data from the read_id bytes. mtd layer detects my NAND as 4K 
> page-sized. So, this shouldn't be a problem I guess.
> 
>>     [3] timings.
> 
> Should I tweak something specific according to the NAND device that I 
> have? Can you give more hints please?
> 
> Thanks,
> Vikram
> 
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